[Specification of statistical graphics in medical research]

Statistical graphics has a long history and is an important mean to present study design, analysis results and conclusions of medical research. A survey of statistical graphs of recent publications in Chinese and English academic journals shows that scientific and technical specifications of statistical graphics are still lacking. Based on the requirements of statistical graphics in prestigious medical journals (NEJM, Lancet, JAMA and The BMJ), this paper summarizes the technical requirements, key points of design of statistical graphs and practical conditions of common statistical graphs to provide reference for clinical researchers.

MicroRNA-30a-3p inhibits malignant progression of hepatocellular carcinoma through regulating IGF1

OBJECTIVE

The purpose of this study was to investigate the expression level of microRNA-30a-3p in hepatocellular carcinoma (HCC), and to further study its relationship with HCC clinical parameters and prognosis and the underlying mechanisms.

PATIENTS AND METHODS

Quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) was performed to examine microRNA-30a-3p level in 44 tumor tissue specimens and paracancerous normal ones collected from HCC patients, and the interplay between microRNA-30a-3p expression and clinical indicators, as well as prognosis of HCC patients was analyzed. Meanwhile, qPCR was also used to further verify microRNA-30a-3p expression in HCC cell lines. In addition, microRNA-30a-3p overexpression and knockdown models were constructed in HCC cell lines, and the impacts of microRNA-30a-3p on HCC cell functions was evaluated by cell counting kit-8 (CCK-8), transwell and cell wound healing assays. Finally, the Luciferase reporting assay was conducted to uncover the underlying mechanism.

RESULTS

In this study, qRT-PCR results showed that the expression level of microRNA-30a-3p in tumor tissues of HCC patients was markedly lower than that in adjacent ones. Compared with patients with high expression of microRNA-30a-3p, the patients with low expression of microRNA-30a-3p had a higher incidence of lymphatic or distant metastasis and a lower overall survival rate. In the Bel-7402 cell line, the proliferation, invasion, and metastasis ability of HCC cells were decreased markedly after microRNA-30a-3p overexpression, while in Hep3B cell line, knockdown of microRNA-30a-3p enhanced the cell proliferation and invasion capacity. In addition, Luciferase reporting assay demonstrated that microRNA-30a-3p could specifically bind to IGF1. Furthermore, Western Blot results also verified a reduced expression of IGF1 after overexpression of microRNA-30a-3p, and an elevated one after knockdown of microRNA-30a-3p. Finally, cell recovery experiment verified that microRNA-30a-3p and IGF1 may regulate each other and thereby together inhibit the malignant progression of HCC.

CONCLUSIONS

MicroRNA-30a-3p expression is significantly decreased in HCC tumor tissue samples, which is associated with lymph node or distant metastasis rate, as well as the poor prognosis of HCC. In addition, this research suggests that microRNA-30a-3p may inhibit the malignant progression of HCC by regulating IGF1.

[Consistency of peripheral whole blood and venous serum procalcitonin in children: a multicenter parallel controlled study]

Objective: To explore the consistency of peripheral whole blood and venous serum procalcitonin (PCT) levels, and the value of peripheral whole blood PCT in evaluating pediatric bacterial infection. Methods: This multicenter cross-sectional parallel control study was conducted in 11 children's hospital. All the 1 898 patients older than 28 days admitted to these hospitals from March 2018 to February 2019 had their peripheral whole blood and venous serum PCT detected simultaneously with unified equipment, reagent and method. According to the venous serum PCT level, the patients were stratified to subgroups. Analysis of variance and chi-square test were used to compare the demographic characteristics among groups. And the correlation between the peripheral blood and venous serum PCT level was investigated by quantitative Pearson correlation analysis.The PCT resultes were also converted into ranked data to further test the consistency between the two sampling methods by Spearman's rank correlation test. Furthermore, the ranked data were converted into binary data to evaluate the consistency and investigate the best cut-off of peripheral blood PCT level in predicting bacterial infection. Results: A total of 1 898 valid samples were included (1 098 males, 800 females),age 27.4(12.2,56.7) months. There was a good correlation between PCT values of peripheral whole blood and venous serum (r=0.97, P<0.01). The linear regression equation was PCT_{venous serum}=0.135+0.929×PCT_{peripheral whole blood}. However, when stratified to 5 levels, PCT results showed diverse and unsatisfied consistency between the two sampling methods (r=0.51-0.92, all P<0.01). But after PCT was converted to ordinal categorical variables, the stratified analysis showed that the coincidence rate of the measured values by the two sampling methods in each boundary area was 84.9%-97.1%. The dichotomous variables also showed a good consistency (coincidence rate 96.8%-99.3%, Youden index 0.82-0.89). According to the severity of disease, the serum PCT value was classified into 4 intervals（<0.5、0.5-<2.0、2.0-<10.0、≥10.0 μg/L）, and the peripheral blood PCT value also showed a good predictive value (AUC value was 0.991 2-0.997 9). The optimal cut points of peripheral whole blood PCT value 0.5、1.0、2.0、10.0 μg/L corresponding to venous serum PCT values were 0.395, 0.595, 1.175 and 3.545 μg/L, respectively. Conclusions: There is a good correlation between peripheral whole blood PCT value and the venous serum PCT value, which means that the peripheral whole blood PCT could facilitate the identification of infection and clinical severity. Besides, the sampling of peripheral whole blood is simple and easy to repeat.

[Correlation between systemic inflammation level and emphysema degree and bone mineral density in chronic obstructive pulmonary disease patients and its mechanism]

Objective: To study the correlation between systemic inflammation level and emphysema degree and bone mineral density in chronic obstructive pulmonary disease (COPD) patients and its possible mechanism. Methods: 90 patients with stable COPD who met the inclusion criteria and 50 controls in the physical examination center during the same period were recruited. All the enrolled objects have collected general clinical data, analyzed peripheral blood samples, measuring the Low-attenuation area of lung and CT value of lumbar 1 vertebra (L1-CT) by chest spiral CT. According to LAA%, COPD patients were divided into 36 cases of the non-emphysema group, 32cases of mild to moderate emphysema group, and 22 cases of severe emphysema group. The correlation between L1-CT value, LAA%, peripheral blood inflammatory factors, and pulmonary function indices in each group was analyzed and compared. Results: The HU value of L1-CT (107±32) in the COPD group was significantly lower than that in the control group (153±30), and the difference was statistically significant (P<0.05). The higher the LAA% in COPD patients was, the lower the value of L1-CT was, and the difference between groups was statistically significant. Compared with COPD patients in the non-emphysema group, peripheral blood neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR), and C-reactive protein (CRP) were all increased in the emphysema group, and the differences were statistically significant (P<0.05). L1-CT was negatively correlated with LAA, PLR, NLR, and CRP while uncorrelated with serum concentration of calcium and phosphorus. Conclusion: The decrease in bone density in COPD patients is closely related to the degree of emphysema. It is associated with increased levels of systemic inflammation caused by COPD itself. Early and timely broad-spectrum anti-inflammatory treatment may have certain clinical significance for the prevention and treatment of comorbidity with osteoporosis.

Transcription factor ZNF703 activates linc-UBC1 to stimulate the progression of glioma

OBJECTIVE

To investigate the role of the transcription factor Zinc finger 703 (ZNF703) in influencing the progression of glioma by regulating linc-UBC1 level.

MATERIALS AND METHODS

Linc-UBC1 level in glioma with different staging and tumor sizes was determined. The potential influences of linc-UBC1 on viability, cell cycle progression, and invasiveness of glioma cells were evaluated. Through RNA binding protein immunoprecipitation (RIP) assay and Dual-Luciferase reporter gene assay, the interaction between ZNF703 and linc-UBC1 was assessed. The rescue experiments were conducted to identify the role of ZNF703 in regulating cellular performances of glioma by interacting with linc-UBC1.

RESULTS

Linc-UBC1 was highly expressed in glioma. Its level was higher in glioma with larger tumor size or advanced staging. The knockdown of linc-UBC1 reduced viability, arrested cell cycle in the G0/G1 phase, and attenuated invasiveness of U87 and LN229 cells. The presence of the binding sites was observed in the promoter regions of ZNF703 and linc-UBC1. The overexpression of ZNF703 could alleviate the inhibited proliferative and invasive potentials in U87 and LN229 cells with the linc-UBC1 knockdown.

CONCLUSIONS

The transcription factor ZNF703 promotes the proliferative and invasive potentials in glioma cells by regulating the transcriptional activity of linc-UBC1.

[Risk assessment of global COVID-19 imported cases into China]

Objective: To assess the risk of COVID-19 foreign imports cases to China. Methods: We collected epidemic data (cumulative daily confirmed cases in each country, cumulative confirmed imported cases), demographic data (population density, population) and information on potential source groups of tourists (the daily estimated number of overseas Chinese, overseas Chinese students, overseas workers, foreign students coming to China and flight passengers) and the global health security index (GHS) to assess and predict risk of imported cases for recent (February 1(st) to April 25(th)) and future (after April 26(th)). Results: Strong positive correlation was found among variables including the number of imported cases, cumulative confirmed cases, attack rate, number of overseas Chinese, number of overseas Chinese students, number of foreign students coming to China, number of flight passengers and GHS. In the recent risk analysis, imported cases of Russian were the highest, followed by United Kingdom, United States, France and Spain. In the future risk prediction, 44 countries including United States and Singapore are evaluated as potential high-risk countries in the future through the attack rate index of each country and the estimated average number of daily passengers. Conclusion: The risk assessment of COVID-19 imported cases can be used to identify high-risk areas in recent and future, and might be helpful to strengthen the prevention and control of the epidemic and ultimately overcome the epidemic.

[Inference of start time of resurgent COVID-19 epidemic in Beijing with SEIR dynamics model and evaluation of control measure effect]

Objective: To infer the start time of the resurgent COVID-19 epidemic in Xinfadi wholesale market in Beijing in June 2020 and evaluate the effect of comprehensive prevention and control measures in this epidemic. Methods: SEIR dynamics model was used to fit daily onset infections to search the start date of this resurgent COVID-19 epidemic in Beijing. The number of cumulative infections from June 12 to July 1 in Beijing were fitted considering different levels of control strength. Results: The current reemerged COVID-19 epidemic in Beijing probably started between May 22 and May 28 (cumulative probability: 95%), with the highest probability on May 25 (23%). The R(0) of the current reemerged COVID-19 epidemic was 4.22 (95%CI: 2.88-7.02). Dynamic model fitting suggested that by June 11, the cumulative number of COVID-19 cases would reached 99 (95%CI: 77-121), which was in line with the actual situation, and without control, by July 1, the cumulative number of COVID-19 cases would reach 65 090 (95%CI: 39 068-105 037). Since June 12, comprehensive prevention and control measures have been implemented in Beijing, as of July 1, compared with uncontrolled situation, the number of infections had been reduced by 99%, similar to the fitting result of a 95% reduction of the transmission rate. The sensitivity analysis showed consistent results. Conclusions: For the emergent outbreak of COVID-19, the dynamics model can be used to infer the start time of the transmission and help tracing the source of epidemic. The comprehensive prevention and control measures taken in Beijing have quickly blocked over 95% of the transmission routes and reduced 99% of the infections, containing the sudden epidemic timely and effectively, which have value in guiding the prevention and control of the epidemic in the future.

[Using Markov Chain Monte Carlo methods to estimate the age-specific case fatality rate of COVID-19]

Objectives: The COVID-19 epidemic has swept all over the world. Estimates of its case fatality rate were influenced by the existing confirmed cases and the time distribution of onset to death, and the conclusions were still unclear. This study was aimed to estimate the age-specific case fatality rate of COVID-19. Methods: Data on COVID-19 epidemic were collected from the National Health Commission and China CDC. The Gamma distribution was used to fit the time from onset to death. The Markov Chain Monte Carlo simulation was used to estimate age-specific case fatality rate. Results: The median time from onset to death of COVID-19 was M=13.77 (P(25)-P(75): 9.03-21.02) d. The overall case fatality rate of COVID-19 was 4.1% (95%CI: 3.7%-4.4%) and the age-specific case fatality rate were 0.1%, 0.4%, 0.4%, 0.4%,0.8%, 2.3%, 6.4%, 14.0 and 25.8% for 0-, 10-, 20-, 30-, 40-, 50-, 60-, 70- and ≥80 years group, respectively. Conclusions: The Markov Chain Monte Carlo simulation method adjusting censored is suitable for case fatality rate estimation during the epidemic of a new infectious disease. Early identification of the COVID-19 case fatality rate is helpful to the prevention and control of the epidemic.

[Principles of dynamics model and its application in forecasting the epidemics and evaluation the efforts of prevention and control interventions]

During the epidemics of COVID-19 in domestic China and recently continuing rapid spread worldwide, a bunch of studies fitted the epidemics by transmission dynamics model to nowcast and forecast the trend of epidemics of COVID-19. However, due to little known of the new virus in early stage and much uncertainty in the comprehensive strategies of prevention and control for epidemics, majority of models, not surprisingly, predict in less accuracy, although the dynamics model has its great value in better understanding of transmission. This comment discusses the principle assumptions and limitations of the dynamics model in forecasting the epidemic trend, as well as its great potential role in evaluating the efforts of prevention and control strategies.

[Fitting and forecasting the trend of COVID-19 by SEIR(+CAQ) dynamic model]

Objectives: Fitting and forecasting the trend of COVID-19 epidemics. Methods: Based on SEIR dynamic model, considering the COVID-19 transmission mechanism, infection spectrum and prevention and control procedures, we developed SEIR(+CAQ) dynamic model to fit the frequencies of laboratory confirmed cases obtained from the government official websites. The data from January 20, 2020 to February 7, 2020 were used to fit the model, while the left data between February 8-12 were used to evaluate the quality of forecasting. Results: According to the cumulative number of confirmed cases between January 29 to February 7, the fitting bias of SEIR(+CAQ) model for overall China (except for cases of Hubei province), Hubei province (except for cases of Wuhan city) and Wuhan city was less than 5%. For the data of subsequent 5 days between February 8 to 12, which were not included in the model fitting, the prediction biases were less than 10%. Regardless of the cases diagnosed by clinical examines, the numbers of daily emerging cases of China (Hubei province not included), Hubei Province (Wuhan city not included) and Wuhan city reached the peak in the early February. Under the current strength of prevention and control, the total number of laboratory-confirmed cases in overall China will reach 80 417 till February 29, 2020, respectively. Conclusions: The proposed SEIR(+CAQ) dynamic model fits and forecasts the trend of novel coronavirus pneumonia well and provides evidence for decision making.

[How to adjust confounders in studies on observational comparative effectiveness: (3) approaches on sensitivity analysis for confounder adjustment]

Confounders are difficult to avoid in studies on observational comparative effectiveness. It is often unclear whether the confounders have been completely eliminated after controlling the measured or unmeasured potential confounding effects or if sensitivity analysis is needed when using the specific statistical methods, under given circumstances. This manuscript summarizes and evaluates the confounding sensitivity analysis methods. Based on different studies, sensitivity analyses need to use different approaches. The traditional sensitivity analysis can be applied for the measured confounders. Currently, the relatively systematic sensitivity analyses for unmeasured confounders would include confounding function, bounding factor and propensity score calibration. Additionally, more investigations are associated with Monte Carlo and Bayesian sensitivity analysis. Reliability of the research conclusion thus may largely be improved when the sensitivity analysis results are consistent with the main analysis.

[Confounder adjustment in observational comparative effectiveness researches: (1) statistical adjustment approaches for measured confounder]

Observational comparative effectiveness studies have been widely conducted to provide evidence on additional effectiveness and to support randomized controlled findings in research. Although this type of study becomes more important over time, challenges related to the common biases which stemmed from confounders, are difficult to control. This manuscript summarizes some statistical methods used on adjusting measured confounders that often noticed in research, regarding the observational comparative effectiveness. Useful traditional methods would include stratified analysis, paired analysis, covariate model and multivariable model, etc.. Unconventional adjustment approaches such as propensity score and disease risk score methods may also be used in studies, for matching, stratification and adjustment. A good study design should be able to control confounders. The limitations of all the post hoc statistical adjustment methods should also be fully understood before being appropriately applied in practical events.

[Regulation of m^(6)A RNA Methylation and Its Effect on Myogenic Differentiation in Murine Myoblasts]

N^(6)-methyladenosine (m^(6)A) has been identified as a conserved epitranscriptomic modification of eukaryotic mRNAs, and plays important biological roles in the regulation of cellular metabolic processes. However, its role in myogenic differentiation is unclear. Here, we altered the m^(6)A RNA methylation level by overexpression of METTL3, and explored the effect of m^(6)A RNA methylation on myogenic differentiation of murine myoblasts in vitro. The m6A RNA methylation level is regulated by exogenous methylation inhibitor cycloleucine (Cyc) and methyl donor betaine (Bet). Therefore, chemical reagents of Cyc and Bet were used to test the regulatory effect of m^(6)A RNA methylation on myogenic differentiation. Results showed that METTL3 and Bet positively regulated the m^(6)A RNA methylation levels, and Cyc negatively regulated m^(6)A RNA methylation levels. In addition, m^(6)A methylation positively regulated myogenic differentiation in murine myoblasts. These findings provide insight in the mechanisms underlying the effect of m^(6)A RNA methylation on myogenesis.

[Application of mendelian randomization methods in causal inference of observational study]

Mendelian randomization (MR) approach follows the Mendel's law of inheritance, which is called "Parental alleles randomly assigned to the offspring", and refers to use genetic variants as an instrumental variable to develop causal inference between the exposure factor and the outcome from observational study. In recent years, with the rapid development of genome-wide association study (GWAS) and various omics data,the disclosure of a large number of aggregated data provides an opportunity for the wide application of MR approach in causal inference. We introduce three methods widely used in MR and then apply them to explore causal relationship between blood metabolites and depressive. The advantages and disadvantages of three methods in causal inference are compared in order to provide reference for the application of MR in observational studies.

[Statistical P values do not dominate scientific research]

Statistical P value and its threshold have been controversial worldwide for a while. Recent heated debate was triggered by two practical issues: unexplainable high false positive rate in biomedical research, and global misunderstood of "statistical significance" in scientific community. Thus, part of scientists suggests applying more stringent significance level (from 0.05 to 0.005), or even giving up the use of significance level. We believe that they are throwing the baby out with the bath water. These suggestions will not contribute to any improvement of this unfavorable situation but will lead the scientific decision-making to a more difficult and subjective corner. Scientists should use statistical P value and threshold only if they correctly understand the soul of statistics-uncertainty. Statistical significance is neither sole nor dominant criterion to measure the scientific value, but an honest assistant. Scientific decision-making should initiate from the scientific experimental design, followed by rigorous implementation and transparent analysis, and synthesize a variety of information to reach a tenable conclusion.

[Association between the frequency of bowel movements and the risk of colorectal cancer in Chinese adults]

Objective: To examine the association between the frequencies of bowel movement (BMF) and the risk of colorectal cancer (CRC). Methods: In this study, 510 134 participants from the China Kadoorie Biobank (CKB) were included, after excluding those who reported as having been diagnosed with cancer at the baseline survey. The baseline survey was conducted from June 2004 to July 2008. The present study included data from baseline and follow-up until December 31, 2016. We used the Cox proportional hazards regression models to estimate the HR and the 95%CI of incident CRC with BMF. Results: During an average follow-up period of 9.9 years, 3 056 participants were documented as having developed colorectal cancer. In the site-specific analysis, 1 548 colon cancer and 1 475 rectal cancer were included. Compared with participants who had bowel movements on the daily base, the multivariable-adjusted HR (95%CI) for those who had more than once of BMF were 1.24 (1.12-1.39) for CRC, 1.12 (0.95-1.31) for colon cancer, and 1.37 (1.18-1.59) for rectal cancer. We further examined the association between BMF and CRC, according to the stages of follow-up, the corresponding HR (95%CI) for CRC, colon and rectal cancer were 1.59 (1.36-1.86), 1.43 (1.14- 1.80), and 1.76 (1.41-2.19) for the first five years, while such associations became statistically insignificant in the subsequent follow-up (P for all interactions were <0.05), as time went on. As for CRC, colon or rectal cancers among participants who had lower bowel movements, the risks were not significantly different from those who had bowel movements everyday. Conclusions: Participants who had BMF more than once a day, appeared an increased risk of CRC in the subsequent five years. Since abnormal increase of bowel movements is easily recognizable, programs should be set up on health self- management and early screening for CRC.

The relationship between small intestinal bacterial overgrowth and irritable bowel syndrome

OBJECTIVE

To explore the relationship between small intestinal bacterial overgrowth (SIBO) and irritable bowel syndrome (IBS).

PATIENTS AND METHODS

Fifty IBS patients in the hospital from January 2015 to December 2015 were assigned to the treatment group, and 50 healthy persons were assigned to the control group. Lactulose hydrogen and methane breath test were performed to measure the percentage of SIBO and oro-cecal transit time (OCTT) in treatment group and control group. These subjects were further assigned to negative SIBO group and positive SIBO group to analyze the scores of symptoms.

RESULTS

The percentage of positive SIBO in the treatment group (72%, 36/50) was significantly higher (p<0.05) than the control group (38%, 19/50). The scores of symptoms on the episode of IBS were not significantly different between the positive SIBO subgroup and the negative SIBO subgroup. The scores of symptoms in breath test were not significantly different between the positive SIBO subgroup and the negative SIBO subgroup. The OCTT in the treatment group (69.34±1.27 min) was significantly lower (p<0.05) than the control group (85.16±1.75 min). The OCTT in the positive SIBO group (88.57±4.62 min) was significantly higher (p<0.05) than the control group (73.42±5.25 min). The results of lactulose hydrogen and methane breath test in the treatment group were positively correlated (r = 0.987, p<0.01). The results of lactulose hydrogen and methane breath test in the control group after oral administration of lactulose were also positively correlated (r = 0.736, p<0.01).

CONCLUSIONS

SIBO was related to IBS and could prolong OCTT, yet not worsen IBS.

[Genetic Polymorphisms of 30 InDel Loci in Ewenki Ethnic Group from Inner Mongolia]

OBJECTIVES

To study the genetic polymorphisms of 30 insertion/deletion （InDel） loci and evaluate their forensic application in Ewenki ethnic group from Inner Mongolia.

METHODS

Peripheral blood samples were collected from 87 unrelated healthy individuals in Ewenki ethnic group. Genomic DNA were extracted, and 30 InDel loci of the samples were multiplex amplified and genotyped. Hardy-Weinberg balance tests were preformed for all loci and genetic parameters were calculated by modified PowerStats v1.2 software. The linkage disequilibrium between loci were tested by SNPAnalyzer v2.0 software. Based on the allele frequencies of 30 InDel loci, the genetic relationships between Ewenki ethnic group and other populations were evaluated by analysis of molecular variance, principal component analysis and phylogenetic reconstruction.

RESULTS

After correction, 30 InDel loci conformed to Hardy-Weinberg equilibrium. It was found that the pairwise InDel loci were in linkage equilibrium after Bonferroni correction. The results of population genetics indicated that Ewenki ethnic group had close genetic relationships with Henan Han and Beijing Han populations; whereas it was significantly different from several populations in Europe and Mexico.

CONCLUSIONS

There are relatively high genetic polymorphisms on 30 InDel loci of Ewenki ethnic group from Inner Mongolia, which can be used as a helpful supplement application for STR detection system.

[The incidence and risk factors of catheter-related-thrombosis during induction chemotherapy in acute lymphocytic leukemia children]

目的

分析初诊急性淋巴细胞白血病（ALL）诱导化疗期外周静脉穿刺中心静脉置管（PICC）患儿导管相关性血栓（CRT）的危险因素。

方法

收集2014年3月1日至2014年12月31日首都医科大学附属北京儿童医院血液肿瘤中心白血病病房行PICC置管的116例初诊ALL患儿临床资料。

结果

①PICC置管后第15天33例（28.4%）患儿发生CRT（CRT组），83例患儿未发生CRT（非CRT组）。②两组在性别、年龄分布、ALL危险度、免疫表型以及置管时两组血常规、凝血功能、是否合并感染、置管静脉方面差异无统计学意义，CRT组右侧置管比例高于非CRT组[75.8%（25/33）对55.4%（46/83），P=0.043]。③CRT组患者均无临床症状，置管第15天D-二聚体高于非CRT组[0.18（0.05~2.45）mg/L对0.11（0.01~5.34）mg/L，P=0.001]。④观察期中出现3例导管相关性并发症，均为导管相关性感染，其中2例并发CRT。⑤置管第33天CRT组26例患者复查B超，19例（73.1%）血栓缩小，6例（23.1%）无明显变化，1例（3.8%）增大。

结论

CRT是初诊ALL患儿诱导化疗期PICC置管的常见导管相关并发症，但症状出现较少，大部分血栓可自行缩小，右侧置管为CRT发生的危险因素；检测D-二聚体水平以及定期进行导管部位B超检查有助于及时发现CRT。

Establishment of a hepatocyte steatosis model using Chang liver cells

The objective of this study was to explore the experimental conditions for hepatocellular steatosis models of Chang liver cells induced by oleic acid (OA). For that, Chang liver cells were induced by different concentrations of OA for different periods. The MTT assay was used to detect hepatic cell activity, the Oil Red O staining was used to observe intracellular lipid droplets accumulation, and the glycerol phosphate oxidase method was used to detect the triglyceride (TG) content in the Chang liver cell. The hepatocellular steatosis models of Chang liver cell were established successfully by inducing with 0.2 mM OA for 24h. TG content in model cells was 379.98 ± 23.19 mg/g, which is significantly different from control cells (185.03 ± 12.68 mg/g; P < 0.01). These were considered proper conditions for establishing hepatocellular steatosis models of Chang liver cells, producing a reliable model for nonalcoholic fatty liver disease research.

TNF alpha inhibits myogenic differentiation of C2C12 cells through NF-κB activation and impairment of IGF-1 signaling pathway

Cachexia or muscle wasting is a common condition that occurs in many chronic diseases. The wasting conditions are characterized by increased levels of TNF-α which was also known as cachectin in the past. But how TNF-α exerts its cachetic effects remains controversial. To clarify this issue, we investigated the impact of TNF-α on C2C12 cell myogenic differentiation. Our results demonstrate that myotube formation was completely inhibited by TNF-α when added to differentiating C2C12 myoblasts. The inhibitory effect of TNF-α on differentiation was accompanied by activation of NF-κB and down regulation of myogenin and Akt. Importantly, TNF-α's effect on differentiation was abolished when IGF-1 was added to the culture. IGF-1 treatment also inhibited NF-κB reporter activity and restored Akt levels. Our data suggest that TNF-α inhibits myogenic differentiation through NF-κB activation and impairment of IGF-1 signaling pathway. The reversal of TNF-α induced inhibition of myogenesis by IGF-1 may have significant therapeutic potential.

Birth-date dependent arrangement of spinal enkephalinergic neurons: evidence from the preproenkephalin-green fluorescent protein transgenic mice

Enkephalin (ENK) has been postulated to play important roles in modulating nociceptive transmission, and it has been proved that ENKergic neurons acted as a critical component of sensory circuit in the adult spinal cord. Revealing the developmental characteristics of spinal ENKergic neurons will be helpful for understanding the formation and alteration of the sensory circuit under pain status. However, the relationship between the embryonic birth date and the adult distribution of ENKergic neurons has remained largely unknown due to the difficulties in visualizing the ENKergic neurons clearly. Taking advantage of the preproenkephalin-green fluorescent protein (PPE-GFP) transgenic mice in identifying ENKergic neurons, we performed the current birth-dating study and examined the spinal ENKergic neurogenesis. The ENKergic neurons born on different developmental stages and their final location during adulthood were investigated by combining bromodeoxyuridine (BrdU) incorporation and GFP labeling. The spinal ENKergic neurogenesis was restricted at E9.5 to E14.5, and fitted in the same pattern of spinal neurogenesis. Further comparative analysis revealed that spinal ENKergic neurons underwent heterogeneous characteristics. Our study also indicated that the laminar arrangement of ENKergic neurons in the superficial spinal dorsal horn depended on the neurogenesis stages. Taken together, the present study suggested that the birth date of ENKergic neurons is one determinant for their arrangement and function.

Role of steps in the dissociative adsorption of water on rutile TiO2(110)

The water-TiO(2) interaction is of paramount importance for many processes occurring on TiO(2), and the rutile TiO(2)(110)-(1×1) surface has often been considered as a test case. Yet, no consensus has been reached whether the well-studied surface O vacancies on the terraces are the only active sites for water dissociation on rutile TiO(2)(110)-(1 × 1), or whether another channel for the creation of H adatoms exists. Here we use high-resolution scanning tunneling microscopy and density functional theory calculations to tackle this long-standing question. Evidence is presented that a second water dissociation channel exists on the surfaces of vacuum-annealed TiO(2)(110) crystals that is associated with the ⟨111⟩ step edges. This second water dissociation channel can be suppressed by blocking of the ⟨111⟩ step edges using ethanol.

Fabrication of large scale nanostructures based on a modified atomic force microscope nanomechanical machining system

The atomic force microscope (AFM) tip-based nanomechanical machining has been demonstrated to be a powerful tool for fabricating complex 2D∕3D nanostructures. But the machining scale is very small, which holds back this technique severely. How to enlarge the machining scale is always a major concern for the researches. In the present study, a modified AFM tip-based nanomechanical machining system is established through combination of a high precision X-Y stage with the moving range of 100 mm × 100 mm and a commercial AFM in order to enlarge the machining scale. It is found that the tracing property of the AFM system is feasible for large scale machining by controlling the constant normal load. Effects of the machining parameters including the machining direction and the tip geometry on the uniform machined depth with a large scale are evaluated. Consequently, a new tip trace and an increasing load scheme are presented to achieve a uniform machined depth. Finally, a polymer nanoline array with the dimensions of 1 mm × 0.7 mm, the line density of 1000 lines/mm and the average machined depth of 150 nm, and a 20 × 20 polymer square holes array with the scale of 380 μm × 380 μm and the average machined depth of 250 nm are machined successfully. The uniform of the machined depths for all the nanostructures is acceptable. Therefore, it is verified that the AFM tip-based nanomechanical machining method can be used to machine millimeter scale nanostructures.

Direct evidence for ethanol dissociation on rutile TiO2(110)

We have studied the interaction of ethanol with reduced TiO(2)(110)-(1 × 1) by high-resolution scanning tunneling microscopy (STM) measurements and density functional theory calculations. The STM data revealed direct evidence for the coexistence of molecularly and dissociatively adsorbed ethanol species on surface Ti sites. In addition, we found evidence for dissociation of ethanol at bridge-bonded O vacancies. The density functional theory calculations support these findings and rationalize the distinct diffusion behaviors of molecularly and dissociatively adsorbed ethanol species, as revealed in time-lapsed STM images.

Trihalomethanes and haloacetic acid species from the chlorination of algal organic matter and bromide

Bromide and algal pollution are important factors influencing disinfection byproduct (DBP) formation and speciation in reservoir water in coastal areas. In this study, the chlorination of model algal cellular compounds (bovine serum albumin, fish oil and starch), Microcystis aeruginosa and its extra-cellular organic matter (EOM) were conducted in the absence and presence of bromide. The main aim of the present study is to explore their potential as precursors for trihalomethanes (THMs) and haloacetic acid (HAAs) speciation upon chlorination in the presence of bromide. The results showed that all brominated THMs species were generated, whereas only bromochloroacetic acid (BCAA) or/and dibromoacetic acid (DBAA) was/were produced as for brominated HAAs (Br-HAAs) from the three model compounds in the presence of bromide. The effect of bromide on Br-HAAs speciation upon fish oil chlorination was more evident than with BSA and starch. There was a good correlation between the species predicted from the model compounds and those obtained from specific algal species. Br-HAAs and Br-THMs species from Microcystis aeruginosa cells or EOM were the same as those from bovine serum albumin in the presence of bromide.

Morphology and function of gill mitochondria-rich cells in fish acclimated to different environments

The objective of this study is to test the hypothesis that morphologically different mitochondria-rich (MR) cells may be responsible for the uptake of different ions in freshwater-adapted fish. Tilapia (Oreochromis mossambicus) were acclimated to high-Ca, mid-Ca, low-Ca, and low-NaCl artificial freshwater, respectively, for 2 wk. Cell densities of wavy-convex, shallow-basin, and deep-hole types of gill MR cells as well as whole-body Ca(2+), Na(+), and Cl(-) influxes were measured. Low-Ca fish developed more shallow-basin MR cells in the gills and a higher Ca(2+) influx than those acclimated to other media. However, fish acclimated to low-NaCl artificial freshwater predominantly developed wavy-convex cells, and this was accompanied by the highest Na(+) and Cl(-) influxes. Relative abundance of shallow-basin and wavy-convex MR cells appear to be associated with changes in Ca(2+) and Na(+)/Cl(-) influxes, suggesting that shallow-basin and wavy-convex MR cells are mainly responsible for the uptake of Ca(2+) and Na(+)/Cl(-), respectively.

[Genetics and expression stability of exogenous gene construct in transgenic mice]

Transgenic mice were produced by introduced exogene construct lambda 106, an expression construct of HBsAg gene directed by bovine alpha-S1 casein gene, with microinjection. Gene integration test with PCR-Southern hybridization, shows that the construct integration rate is 56% (17/30) and expressed rate, by ELISA, of target gene product HBsAg is 100% (8/8) in the first generation. Generation trailing test suggests that the gene construct can be stably inherited across generation after generation, and expressed more or less than parents among offspring. However positive rate of offspring does not follow genetic ratio that exogenous gene can be integrated randomly into a single site on chromosomes. There may be a machinery of multi-sites for exo-gene integration. Changes of the target gene expression in the offsprings may be related to position effect, changing of gene copy number and changing of chromatin imprinting pattern when parent's genome information was delivered to their progeny.

Preparation and in vitro evaluation of B-lipiodol as a boron delivery agent for neutron capture therapy of hepatoma

BACKGROUND

We prepared boron containing lipiodol (B-lipiodol), elucidated the retention of B-lipiodol in hepatoma cells and evaluated the in vitro cellular toxicity of B-lipiodol for neutron capture therapy.

MATERIALS AND METHODS

Human hepatoma HepG2 cells were used to examine the uptake and retention of B-lipiodol. Light microscopes were used to examine the interaction and retention of B-lipiodol globules in individual hepatoma cells. Boron and lipiodol concentrations were determined by inductively coupled plasma-atomic emission spectroscopy and neutron activation analysis, respectively.

RESULTS

The boron concentration in B-lipiodol drug could reach 2500 ppm. B-lipiodol could be stably retained in serum and culture medium. HepG2 cells appeared proficiently at internalization and persistent retention of B-lipiodol. The boron concentration reached 3.5 micrograms/10(6) cells without approaching saturation at 48 h treatment.

CONCLUSION

Hepatoma cells could actively uptake B-lipiodol and a sufficient amount of boron was retained inside the HepG2 cells which could be used for neutron capture therapy.

Alpha 2B-adrenergic receptors: immunolocalization and regulation by potassium depletion in rat kidney

Regulation of transport processes in renal epithelial cells in response to alpha 2-adrenergic receptor (alpha 2-AR) stimulation is likely due to specific effects of the A-, B-, or C-subtype alpha 2-AR. The purpose of the present study was 1) to examine the precise localization, using subtype-specific antibodies, the B-subtype alpha 2-AR protein, the most abundant alpha 2-AR in rat kidney; and 2) to determine the effect of dietary potassium restriction, a factor known to increase alpha 2B-ARs, on the distribution of receptors. We employed a method to generate a specific antibody to the third intracellular loop of the alpha 2B-AR and demonstrated the specificity of this antibody. Our results demonstrated, for the first time, evidence for the alpha 2B-receptor protein in the basolateral membrane of proximal convoluted and straight tubules. No specific immunoreactivity was detected in other nephron segments. Finally, the increase in alpha 2B-AR expression observed previously was due to the recruitment of alpha 2B-ARs to the basolateral membrane of proximal tubules.

Tissue potassium, selenium, and iron levels associated with gastric cancer progression

The contents of 10 minor and trace elements in histologically confirmed gastric adenocarcinomas and their corresponding normal gastric mucosal tissues obtained from 39 patients at the time of gastric resection were simultaneously determined by instrumental neutron activation analysis. Specimens were irradiated by reactor neutrons and subsequently subject to direct analysis using a high-resolution HPGe gamma-spectrometer. Univariate analysis revealed that gastric cancer tissues had significantly higher concentrations of Fe, K, Mg, Na, Rb, Se, and Zn than normal gastric mucosal tissues. However, multivariate analysis found that Fe, K, and Se were independent elements that associated with gastric cancer. Upon further evaluation of their clinical significance, we found a high tissue K level was related to lymphatic duct metastasis. High Se tissue levels were linked to intestinal type adenocarcinoma. A positive correlation was found between high Fe levels and vascular involvement. These findings suggest that Fe and K are associated with gastric cancer progression. Se is involved in carcinogenesis of stomach in high-risk areas. The mechanisms that underlie the corresponding pathohistological features deserve further study.

Apical membrane and intracellular distribution of endogenous alpha 2A-adrenergic receptors in MDCK cells

The purpose of the current studies was to characterize the endogenous alpha 2-adrenergic receptor (AR) subtypes present in Madin-Darby canine kidney (MDCK) cells and to determine their level of expression and pattern of distribution. By saturation binding analysis with [3H]MK-912, MDCK cells expressed high levels of alpha 2-ARs with a maximum receptor density (Bmax) of 798 +/- 55 fmol/mg protein and an equilibrium dissociation constant (Kd) of 0.98 +/- 0.32 nM. Competitive binding studies using prazosin, oxymetazoline, phentolamine, and epinephrine to displace [3H]MK-912 demonstrated inhibition constant (Ki) values of 1,270 +/- 250, 5.0 +/- 0.4, 5.5 +/- 0.3, and 392 +/- 150 nM (n = 3), respectively. In Northern blot analysis we found that MDCK cells expressed transcripts encoding alpha 2A-AR and not alpha 2B-AR or alpha 2C-AR. Surface binding experiments suggested that approximately 60% of alpha 2A-ARs are distributed at the cell surface domain. Specific binding of [3H]MK-912 to soluble apical and basolateral surface proteins isolated by surface biotinylation indicated the expression of surface alpha 2A-ARs was limited to the apical domain of MDCK cells. No alpha 2A-ARs were detected on the basolateral surface. We conclude that endogenous alpha 2A-ARs are targeted to the apical domain of MDCK cells and that the intracellular compartment may contain ARs as a reservoir for de novo cell surface expression or, alternatively, may represent internalized receptors.

Analysis of elemental absorption and excretion in mice bearing malignant ascites

Feces, kidney, and small intestine were sampled from the mice bearing malignant ascites at different stages of tumor growth to investigate the kinetics of elemental distribution in the body. The contents of 14 elements in samples were determined by instrumental neutron activation analysis (INAA). The elements Br, Cl, Cu, Na, Se, and Zn increased, whereas Mn and Rb decreased in kidney with the growth of the tumor. The elements Cl, Na, and Fe, however, appeared to have significantly different behavior in the small intestine.

Determination of whole-body nitrogen and radiation assessment using in vivo prompt gamma activation technique

Body nitrogen content in the phantom is measured by semiconducting and scintillation spectrometers using in vivo prompt gamma-ray activation analysis technique. The effective dose rate equivalents for sensitive organs and tissues inside the phantom are assessed by dosimetric measurement and neutron transport calculation. The bismuth germanate scintillator is found superior to the germanium semiconducting detector to quantitatively measure the photopeak of the 10.829 MeV prompt gamma-ray emitted from the 14N(n, gamma) reaction. Recommended scanning period for current setup using the BGO detector is 1 h on the modified mobile nuclear reactor. The effective dose equivalents from both neutrons and gamma-rays are estimated around 63 microSv per scan in the phantom test, making it a safe and reliable nuclear analytical method for in vivo body nitrogen measurement.

Cytochrome b560 (QPs1) of mitochondrial succinate-ubiquinone reductase. Immunochemistry, cloning, and nucleotide sequencing

Mitochondrial succinate-ubiquinone reductase is composed of two parts, a water-soluble succinate dehydrogenase and a two-polypeptide membrane-anchoring protein fraction (QPs). The larger polypeptide of QPs is believed to be associated with cytochrome b560 (QPs1). The structure of QPs1 was studied by immunochemistry and molecular cloning and sequencing. Antibodies against QPs1 were raised in rabbits, purified, and characterized by enzyme-linked immunosorbent assay and Western blotting. The purified antibodies inhibited 75% of the reconstitutive activity of QPs and reacted with both submitochondrial particles (SMP) and mitoplasts. The binding of these antibodies to SMP was greatly increased when succinate dehydrogenase was removed from SMP by alkaline treatment, indicating that QPs1 is a transmembranous protein and that some of its specific epitopes are covered by succinate dehydrogenase. Anti-QPs1 antibodies were used to screen one cDNA clone encoding QPs1 from a bovine heart cDNA lambda gt11 expression library. The cDNA insert is 946 base pairs with an open reading frame of 396 base pairs that encodes for 132 amino acid residues. The molecular weight of QPs1, calculated from the deduced amino acid sequence, is 14,320. Although the apparent molecular weight of QPs1, estimated by high resolution SDS-polyacrylamide gel electrophoresis, is approximately 11,000, the existence of a presequence was ruled out by mass spectrometric analysis of protein fragments. QPs1 is a very hydrophobic protein. Three probable membrane-spanning segments were revealed by a hydropathy plot of the sequence. QPs1 has a higher sequence similarity to the sdhC peptide of Escherichia coli than to the sdhC peptide (cytochrome b558) of Bacillus subtilis. Like the bacterial proteins, QPs1 has 2 conserved histidines at positions 34 and 90. The conserved nature and similar location of these 2 histidines, on the matrix-side surface of the membrane, suggest that they are involved in heme ligation of cytochrome b560.

Preparation of [131I]lipiodol as a hepatoma therapeutic agent

An isotopic exchange method was used to label lipiodol with 131I. The labelling efficiency was > 92.5%, and the radiochemical purity of [131I]lipiodol was above 98% as determined by ITLC. The influencing factors e.g. the heating temperature, reaction time, pH and storage conditions were studied and the optimum conditions were determined. In a pilot study injecting [131I]lipiodol for the treatment of hepatoma, about 70% of hepatoma patients had a response to the treatment with a reduction of alpha-fetoprotein and decrease of hepatoma sizes. The overall median survival was 9 months (range 2-17 months).

[Changes in hemorheology of traumatic optic nerve atrophy]

Whole blood viscosity (WBV), plasma viscosity (PV), hematocrit, erythrocyte sedimentation rate (ESR) and fibrinogen were assayed in 20 patients with traumatic optic nerve atrophy. The results of each item in the above examinations has been compared with that of the control group. It has been demonstrated that WBV, PV, ESR and fibrinogen in the patient group were significantly higher than that in the control group (P less than 0.01). But the ESR and fibrinogen of the treatment group were significantly lower than that in the pretreatment group (P less than 0.01). The authors suggest that the result of changes in hemorheology of traumatic optic nerve atrophy is a kind of reverse phenomenon.

Report of a pilot study of intra-arterial injection of I-131 lipiodol for the treatment of hepatoma

This pilot study in 10 hepatoma patients investigated the feasibility of using selective targeting of radioisotope (I-131) lipiodol in the treatment of hepatoma patients. Lipiodol is a contrast medium that selectively goes to hepatoma and remains there for a long period as compared with that in normal liver and other tissues. Lipiodol was labelled with I-131 and infused into the hepatoma via the hepatic artery. Selective targeting of I-131 to hepatoma was demonstrated with a radiation dose ratio (hepatoma to normal liver) of up to 25 to 1. The biodistribution data of I-131-lipiodol in this study also confirmed the selective targeting of the radioisotope (I-131) to the hepatoma. Tumor radiation dose up to 26,000 rads can be delivered by this method. The treatment results were encouraging. About 70% of hepatoma patients had response to the treatment with reduction of alpha-fetoprotein and decrease of hepatoma sizes. The overall median survival was 9 months (range 2-17 months). This treatment was simple, safe, effective, non-expensive and well tolerated by all patients without major side effects. The optimal dose, schedule, duration of this treatment are still under investigation.